This is how science works: one set of researchers puts out a new idea, and others try to knock it down. Or so Ward and Day estimated - whereupon other scientists immediately piled in to insist that they had got the geology wrong, or the volcanology, or the rate at which tsunami waves lose height over long distances. Hundreds of metres high at first, the tsunamis waves would probably be down to one hundred metres by the time they reached Spain, and perhaps only 25 metres high when they struck the North American coast from Florida to Newfoundland. They estimated that the giant waves generated by a flank collapse would hit the Moroccan and Spanish coasts in two to three hours, and make it all the way across the Atlantic to strike the Brazilian, US and Canadian coasts in nine hours. The original scientific article warning of a possible mega-tsunami from La Palma was written by Steven Ward and Simon Day in 2001. What we don’t know is the size and reach of the resulting tsunami. The chances are strongly against it happening this time, because Cumbre Vieja has been erupting on average once a century since records began, and there has not been a big slide there for at least 125,000 years.īut there will eventually be another collapse on La Palma and then a tsunami, maybe tomorrow, maybe in 100,000 years or so. That’s why volcanologist Joan Martí, when asked if the flank of Cumbre Vieja might slide into the sea and cause a huge tsunami, replied that “it is possible, but it is not likely.” There have been at least 10 in the past million years. The volcanoes constantly rebuild the islands, too, so massive landslides are a normal part of their geology. The biggest single landslide, about half a million years ago, dumped an estimated 200 cubic kilometres of rock into the Atlantic. La Palma and its neighbour El Hierro, the westernmost islands of the Canaries, are so volcanic that similar cone collapses have removed about half of their above-water mass during the past million years. Part of the main cone of Cumbre Vieja (‘old summit’) collapsed last weekend. The eruption is now more than two weeks old, but the explosions and lava flows are still increasing. The media definitely overhyped that risk when it was first suggested 20 years ago, so now they have to work the other side of the street.īut the original story still has legs. ‘Don’t bother your pretty head about it’ is the prevailing media take on the risk of the volcanic eruption on La Palma in the Canary Islands turning into a mega-tsunami disaster.
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